Apparatus for the diffusion of volatile products

ABSTRACT

AN APPARATUS FOR DIFFUSION OF VOLATILE LIQUIDS INTO THE ATMOSPHERE BY EVAPORATION IS DISLCOSED WHICH COMPRISES A RESERVOIR CONTAINING THE LIQUID TO BE EVAPORATED INTO WHICH DIPS A FEEDER WICK JOINED TO AN EVAPORATOR MOUNTED ON A WALL OF THIS RESERVOIR; A TUBE SURROUNDING THE WICK FOR AT LEAST PART OF ITS HEIGHT, AND A DESTRUCTIBLE CLOSURE DEVICE INTERRUPTING THE COMMUNICATION OF THE INTERIOR ORIFICE OF THE WICK TUBE WITH THE ATMOSPHERE BEFORE USE AND MEANS SUCH AS A BLADE OPERABLE FROM THE OUTSIDE TO DESTROY THE CLOSURE DEVICE AT THE MOMENT OF PUTTING THE APPARATUS TO USE. THE RESERVOIR PREFERABLY ALSO CARRIES A TUBE COMMUNICATING THE GASEOUS VOLUME INSIDE TO THE ATMOSPHERE, WHICH IS PREFERABLY SEALED OFF BEFORE USE IN A SIMILAR MANNER AS THE WICK TUBE AND MUST BE OPENED TOGETHER WITH THE LATTER. IN ANOTHER MODIFICATION OF THE APPARATUS, THE CLOSURE DEVICE IS NONDESTRUCTIBLE AND COMPRISES A SEALING PLUG LOCATED IN THE PROJECTION OF THE FEEDER WICK AND WHICH CROSSES THE EVAPORATOR, THE UNIT FORMED BY THE PLUG AND THE WICK BEING SLIDABLE BETWEEN A CLOSURE POSITION AT WHICH THE PLUG OBTURATES THE WICK TUBE AND AN OPEN POSITION IN WHICH THE PLUG IS PULLED BEYOND THE EVAPORATOR THIS LATTER BEING THEN IN CONTACT WITH THE FEEDER WICK. THE ENTIRE APPARATUS CAN BE COVERED BY A HOOD CONTAINING A DIFFUSER WALL.

United States Patent [72] lnventors Claude Hennart Aubervllliers;Georges Martin; Jean Claude Balland, Poitiers, France [21] Appl. No.839,726 {22] Filed July 7, 1969 [45] Patented June 28,197l [731 AssigneeClba-Geigy Corporation Ardsley, N.Y.

[54] APPARATUS FOR THE DIFFUSION 0F VOLATILE PRODUCTS 11 Claims, 10Drawing Figs.

[52] U.S. Cl. 239/47, 239/309 [51) Int. Cl r B65d 45/16 [50] Field ofSearch 239/47, 44, 49, 50,57, 58, 309; 222/l 87 [56] References CitedUNITED STATES PATENTS 3,028,100 4/1962 Xenakis et al. 239/47 3,134,5445/1964 Copley 239/44(X) 3,l 35,565 6/1964 Bingham 239/44(X) PrimaryExaminer- M. Henson Wood, Jr. Assistant Examiner-Thomas Cv Culp, Jr.Attorney-Wenderoth, Lind & Ponack ABSTRACT: An apparatus for diffusionof volatile liquids into the atmosphere by evaporation is disclosedwhich comprises a reservoir containing the liquid to be evaporated intowhich dips a feeder wick joined to an evaporator mounted on a wall ofthis reservoir; a tube surrounding the wick for at least part of itsheight, and a destructible closure device interrupting the communicationof the interior orifice of the wick tube with the atmosphere before useand means such as a blade operable from the outside to destroy theclosure device at the moment of putting the apparatus to use.

The reservoir preferably also carries a tube communicating the gaseousvolume inside to the atmosphere, which is preferably sealed off beforeuse in a similar manner as the wick tube and must be opened togetherwith the latter.

In another modification of the apparatus, the closure device isnondestructible and comprises a sealing plug located in the projectionof the feeder wick and which crosses the evaporator, the unit formed bythe plug and the wick being slidable between a closure position at whichthe. plug obturates the wick tube and an open position in which the plugis pulled beyond the evaporator, this latter being then in contact withthe feeder wick. The entire apparatus can be covered by a hoodcontaining a diffuser wall.

PATENTEDJUN2819TI 3581.968

K 9 Y K 3 6 11: if) Q Ts E: LB J9 CLAUDE HENNART, GEORGES MARTIN andJEAN CLAUDE BALLAND Inventors Attorneys PATENTED JUN28 1911 SHEET 2 [1F4 CLAUDE I'IENNART GEORGES MARTIN and JEAN CLAUDE BALLAND Inventors BY##MAZXLA M Attorneys PATENTEUJUN28I971 (587,968

SHEET l 0F 4 CLAUDE HENNART GEORGES MARTIN and JEAN CLAUDE BALLANDInventors BmWQKl/VM Attorneys APPARATUS FOR THE DIFFUSION OF VOLATILEPRODUCTS DESCRIPTION OF THE INVENTION The present invention relates toan apparatus for ensuring the diffusion into the atmosphere byevaporation of volatile liquid substances such as insecticides, insectrepellents, bactericides, deodorants, perfumes, sanitary products andothers.

it is well known to effect the evaporation of liquids of this kind bymeans of apparatus comprising a reservoir containing the liquid intowhich dips a wick which projects outside the reservoir passing throughan opening therein.

The principal advantage of these apparatus resides in the possibility,in given conditions, of obtaining evaporation rates constant in time, asopposed, for example, to apparatus constituted by an absorbate, anadsorbate or a solution in a body of solid material.

Another advantage of evaporators with wicks ,resides in the possibilityof delivering a larger quantity of vapor when the circulation of air isgreater; this property is very interesting because it is evident thatfor maintaining proper efficacy in an aerated room, the discharge ofvapors should be larger than in a closed room, as a result of the lossesdue to aeration. This property permits, at the-time of adjusting theapparatus, the limiting of the evaporation rates in a closed room to thequantity strictly necessary which is of economic importance when activematerials of high cost are used and/or gives greater safety when toxicactive materials are used. No other evaporation device possesses such aproperty.

A third advantage of apparatus with wicks is that they allow the totalusing up of the liquid to be evaporated, evaporation only ceasing on theexhaustion of the liquid; in solid compositions, on the other hand, theyield does not generally exceed 50 percent. The disappearance of liquidallows, besides, the end of use of the device to be noted, which is notpossible using a solid composition.

The principal inconvenience of an apparatus with a wick stems from thedanger of spillage of liquid, following an accidental turning over ofthe device, during use and/or during transportation.

This loss of liquid is particularly to be feared when the device is forthe evaporation of insecticidal or bactericidal liquids, of which thecontent or presence in too great quantity in the atmosphere is generallyharmful, and can even be fatal to man In addition, in most cases, theliquids used can damage furniture or clothingon which they are spilt.

Another disadvantage exists, as serious as the disadvantages mentionedabove. When the volatile liquid is formed by a phosphoric ester, itgenerally has the inconvenience of being rapidly hydrolysed when it isexposed to ambient air over a large surface area, Now, is is exposed toambient air over a large surface area. Now, it is often possible thatthe ambient humidity penetrates into the interior of a wick evaporator,or that there is contact between the humidity and the phosphoric esterin the wick and all over its evaporative surface.

Apparatus with wicks which try to avoid these disad vantages are alreadyknown.

For example, according to certain constructions, the wick is movablewith respect to the reservoir and can be enclosed therein with the aidofa movable cover. Such a system is relatively complex and does not stopthe liquid spreading out if the apparatus is accidentally turned over.

According to another construction, an evaporator surface is fed bypressure of a propellant gas, but this construction makes the apparatusburdensome, and if the propellant gas escapes, it stops working.

There has also been described an apparatus provided with a capillarywick, fed with liquid by gravity, this wick being connected to adiffuser placed thereabove. This construction makes the protection ofthe evaporator surface difficult and necessitates a capillary wick ofprecisely measured section, which is difficult to obtain.

Other known apparatus is provided with a more or less complex valve forpreventing access of atmospheric humidity during storage. These valveseasily suffer from grave disadvantages on account of their complexconstruction and their tendency to corrosion and obstruction in use.

In addition, it is known to construct apparatus comprising a dippingwick which feeds an evaporation surface formed by a disc of absorbentmaterial. This latter increases the possibility of diffusion of the wickand, as a result, the discharge thereof. However, it could be useful inthis type of apparatus to stop the discharge at will, by means of asimple operation. Now, the evaporation surface is opposed to the returnof the wick. The

. invention seeks also to remedy these limitations.

According to the invention, the apparatus for diffusion into theatmosphere, of volatile liquids by evaporation, comprises :a reservoircontaining the liquid to be evaporated into which dips a feeder wickjoined to an evaporator mounted on this reservoir, and the wall of thereservoir on which the evaporator is mounted, carries a tube internal ofthe reservoir and directed toward the base thereof, this tubesurrounding the I wick for at least part of its height, this apparatusaccording to the invention being characterized in that it comprises adestructible closure device interrupting the communication of theinterior orifice of the wick tube with the atmosphere before use, andmeans to destroy the said closure device at the moment of its being putto use.

According to another embodiment of the invention, the reservoir alsocarries a tube joining the gaseous interior volume to the atmosphere.This atmosphere communication tube prevents any escape of liquidresulting from accidental excess pressure in the gaseous phase of thereservoir.

In particular, the interior orifice of the wick tube is initially sealedby a diaphragm, and means are provided to ensure perforation of thisdiaphragm when the apparatus is put to use. If the apparatus comprisesan atmosphere communication tube, a similar diaphragm is advantageouslymounted on this tube.

Another embodiment of the apparatus according to the invention providesthat the means for perforating the diaphragm comprise a piercing pinlocated in the wick tube, the other end of which extends to the outsideto permit of manual operation.

The wick tube thus fitted out ensures the maintenance of the wick and ofthe evaporator joined thereto. Further, it permits stopping the rate offeed by simply turning the apparatus upside-down.

Preferably, it is also provided that, at the point of putting the deviceto use, the volume of liquid introduced into the reservoir should besuch that, in all positions of stable equilibrium of the reservoir,other than its use position, the level ofliquid in this reservoir islocated below the interior orifice of the wick tube. In theseconditions, any loss of liquid in the case of accidental tipping over ofthe apparatus is prevented.

In another simple embodiment of the apparatus according to anotheraspect of the invention in which a nondestructible closure apparatus isused, the communication of the wick tube with the atmosphere isprevented by means ofa plug provided with a manipulatable plug whichtraverses the evaporator and slides sealingly in the said tube. Beforeuse, this plug interrupts the communication between the wick in theinterior of the tube and the evaporator and it is necessary to pull theplug up to establish such communication.

Other details of the invention will be apparent from the descriptionhereafter.

In the attached drawings, which are given as nonlimitative examples:

FIG. 1 is a schematic elevational view ofa first construction, theapparatus being shown in its condition before being put to use;

FlGS. 2 and 3 are partial schematics in axial section showing methods ofconstruction of the wick tube with different closure devices anddestruction means.

FIG. 4 is an elevational sectional view on lines lV-lV of FIG. 5 of acommercial construction of the apparatus;

FIG. 5 is a corresponding plan view partly cutaway and partially insection;

FIG. 6 is an axial section on a larger scale of the axial portion oftheapparatus shown in FIGS. 4 and 5',

FIG. 7 is an axial section of another construction of the ap paratusaccording to the invention with a destructible closure apparatus;

FIGS. 8 and 9 are schematics on a large scale showing the wick in useand out of action according to a variant of the apparatus according tothe invention with a nondestructible closure apparatus;

FIG. 10 is an axial section of another commercial construction of theapparatus according to the invention with a nondestructible closureapparatus.

Referring to FIG. 1 of the attached drawings, it can be seen that, in aschematic construction, the evaporator comprises basically a reservoir 1in which is located the liquid 2 to be evaporated. The reservoir 1 isbounded by two faces 3 and 4, of which one is pierced by an orifice 5from which an axial tube 6 extends toward the other face. In the exampledescribed, the other orifice of tube 6 is located a short way from theface 3 which serves as a base, in the normal position of use.

An absorbent element 8, hereinafter called a feeder wick, is located intube 6 and is joined to an evaporation element 9, hereinafter referredto as the evaporator, located near to face 4.

Certain of the characteristics of the foregoing parts will now bedetailed.

The shape, capacity and nature of reservoir 1 are not critical, theyonly depend on the desired use.

The material forming the reservoir can be, for example, glass,porcelain, a metal such as aluminum, iron, copper, or alloys thereof, ora high molecular weight material such as polyethylene, polypropylene,polystyrene, polyvinylchloride, fluorinated or chlorofluorinatedpolymers, polyvinyl esters, polyacrylic esters, polymethacrylic estersor copolymers thereof. It can also be, without any resultingrestriction, a resin of the type called ionomeric, a bakelite, anebonite, a ureafor maldehyde, phenolformaldehyde, melamine formaldehyde,aniline formaldehyde or phenolfurfuraldehyde condensation product or apolyamide.

The methods of manufacturing the reservoir are known ones such asstamping, moulding, blowing, injection moulding, thermoforming,extrusion, welding, soldering, assembling, and the like.

The material forming the reservoir 1 can be protected from the action ofthe liquid to be evaporated, particularly from corrosion, by means ofalining formed ofa metal, an oxide, an enamel, a varnish, a polymer orother substance suitable for ensuring the preservation of thisreservoir. The lining can be deposited by any known method such as, forexample dipping, centrifugal spraying, plasma spraying, glazing,anodisation, or electrodeposition.

The shape of reservoir 1 is cylindrical in the example described.However, it can also be spherical, truncated conical, cylindroconical,biconical, ovoid pyramidal, bipyramidal, cubic or parallelipipedic; itcan also, for example, be of a shape formed by the revolution of variouscurves and/or folded lines; the shape can also be entirely regular.

Some examples of such methods of construction will be given below.

The safety tube 6 surrounds the wick 8; the walls of tube 6 can be incontact with this wick, or, on the other hand, can be spaced therefrom.It is not necessary that the tube 6 descend as far as the base 3 of thereservoir ifthis is not intended to be completely filled. It issufficient, in such a case, that the length of the tube be such as torise above the level ofthe liquid when the reservoir is in theupside-down position.

The shape of the tube is not critical. lts section may be round,elliptic, oval, triangular, square, rectangular or polygonal. The shapeand dimensions of the section can differ at different heights of thetube, such that the tube can, for

reasons of ease of manufacture, for example, be broader at its base thanat its upper part.

The materials usable for making the safety tube 6, are, in particular,those noted for the manufacture of the reservoir. The material chosencan be the same as that of the reservoir or different therefrom.

According to a particular version of interest, the wick 8 and the tube 6are formed by one and the same piece, ofa material chosen to be suitablefor the material serving as feeder, and which can be renderedimpermeable about its periphery. For example, a bar of porcelain orsintered glass can be used, the outer surface of which is renderedimpermeable by glazing, the two ends in contact with the liquid and withthe evaporative surface having no glazing; the glazing can be replacedby any other impermeabilising treatment, such as, for example, thedeposition of a varnish, of an elastomer or of a plastomer. The bar canalso be replaced by a tube of which the inner wall has kept itsporosity.

The feeder wick 8 has a porous or fibrous structure. For example, it canbe formed by a felt, tissue, paper or unsized card, an unvarnishedporcelain, alumina, terra cotta, sintered glass or metal or anagglomerate of wood, glass or stone fibers.

The shape of the feeder wick 8 is not critical. It can be, for example,of square, rectangular, circular or annular section, this sectionhaving, for example, an area of between 0.2 and mm?, preferably between2 and 200 mm The length of the wick depends primarily on the height ofreservoir 1; it is chosen, preferably, in such fashion as to reach thebase of the reservoir and can thus completely exhaust its contents. Thewick 8 can also be constructed by means of a capillary tube of glass orany other material, or a bundle ofsuch tubes.

The evaporator 9 is formed from a porous or fibrous material, such as,for example, a felt, a tissue, paper or unsized card, unvarnishedporcelain, alumina, terra cotta, sintered glass or metal or anagglomerate of wood fibers.

The shape ofevaporator 9 is not critical. For example, it can be a disc,square, rectangle, cone or spherical cap with walls which are smooth ornot, flat, undulating, grooved, chequered, or formed in any other waysuitable for allowing evaporation of the particular liquid used. Thethickness of the evaporating surface is likewise not critical and can befrom a fraction of a millimetre, for example in the case of paper, to afew centimeters, for example in the case of a felt. The preferredthicknesses of the invention are always between 0.5 and 5 mm.

A single face of the evaporator 9 can be used as evaporative surface,the or each other face being masked or applied to a .support; on theother hand, several or all of the faces of the said material may beused.

Since the rate of evaporation, for each liquid, is a function of thesize of the evaporative surface, the dimensions of this surface arechosen so as to obtain the desired evaporation rate, which, of course,varies from one liquid to another according to the volatility and vaporpressure. Generally, the evaporative surface is between 2 and 300 cm andpreferably between 10 and 100 cm The evaporator 9 can rest on the upperwall 4 of the reservoir l or on a separate support. It can be placed insimple contact or can be fixed at one or more points. It may be held inthe chosen position by its own rigidity or by supports or a casing ofany material, for example a metal or plastic material, of horn, amineral material or a hardened rubber.

The same material can be used to form the wick 8 and the evaporator 9,or one can employ different materials. Likewise, the assembly of wick8/evaporator 9, can constitute one piece or, on the other hand, separatepieces.

In order to allow liquid to be evaporated to pass easily from the wick 8to the evaporator 9, when these two elements are separate pieces, it ispreferred to ensure a close contact between them. This contact isestablished, for example, by juxtaposition, wedging, sewing, sticking,clipping or force fitting.

The volatile liquids 2 which are to be introduced into reservoir I ofthe evaporator apparatus according to the invention are substances ofwhich the vapors possess a useful activity in the atmosphere. Suchactivities are, for example: insecticide, insect repellent, rodentrepellent, bactericide, germicide, larvicide, disinfectant, humidifier,odorant or deodorant.

These substances can be used alone or in admixture or in the form ofsolutions. Among the suitable insecticidal or insect repellentsubstances which may be noted, but without limitation thereby, areparadichlorobenzene, trichloro-, tetrachloro pentachloroandhexachlorobenzene, naphthalene, bromonaphthalene, dichloronaphthalenes,lindane, aldrin, dimethyl phthalate, citronellol and phosphoric esterssuch as the natural essences of vervain (citronelle) neroli or bourbon.

Among the bactericidal, germicidal and disinfectant substances there canbe noted phenol, the cresols, eugenol, thymol, the chlorophenols, thechlorocresols, menthol and its esters, iodine and formaldehyde.

The preferred insecticidal substances are the phosphoric esters chosenfrom those defined by the following general formula:

( RO O-Rs I R.O A v V wherein A is oxygen or sulfur, R is alkyl, R, isalkyl and R is one of the following groups: X X

wherein R and R,, are the same or different and are hydrogen, halogen oralkyl, and X is halogen; (3) R. Rd

wherein R, and R, and X have the meanings given above.

As non limitative examples of compounds corresponding to the generalformula, there may be noted the following phosphoric or thionophosphoricesters: 2,2-dichlorovinyl dimethyl phosphate 2,2-dichlorovinyl diethylphosphate 2,2-dichlorovinyl dipropyl phosphate 2,2-dichlorovinyl dibutylphosphate 2,2-dibromovinyl dimethyl phosphate 2,2dibromovinyl diethylphosphate 2,2-dibromovinyl dipropyl phosphate 2-bromo-2-chlorovinyldimethyl phosphate 2-bromo-2-chlorovinyl diethyl phosphate2,2-dichlorovinyl methyl ethyl phosphate l,2-dibromo-2,2-dichloroethyldimethyl phosphate l,2-dibromo-2,2-dichloroethyl diethyl phosphatel-bromo-2,2,2-trichloroethyl dimethyl phosphatel-bromo-2,2,2-trichloroethyl diethyl phosphate l,2,2,2,-tetrabromoethyldimethyl phosphate l,2,2,2,-tetrabromoethyl diethyl phosphatel,2dibromo-2,2dichloropropyl dimethyl phosphatel,2-dibromo-2,2-dichloropropyl diethyl phosphate 2,2-dichloro-2-methylvinyl dimethyl phosphate 2,2-dichloro2-methyl vinyl diethyl phosphatethe corresponding thiophosphonates.

The preferred phosphoric esters are those in which R, is a CI-I==CC1group, i.e., the 2,2-dichlorovinyl dialkyl phosphates. Among these thereis particularly 2,2-dichlorovinyl dimethyl phosphate, known under thename of DDVP and DlCl-ILORVOS.

To ensure absolute sealing of the reservoir 1, before usage of theapparatus there is provided, according to the invention, a diaphragmobturating the wick tube 6 which is perforated at the moment of use. Inthe version of FIG. 1, the diaphragm is formed by a membrane 41 at thelevel of orifice 7, and which can be formed by moulding at the same timeas tube 6. In order to enable the apparatus to be put to use there isprovided a sliding piercing pin 42 located in the tube 6, for example onthe axis of the wick 8.

The piercing pin 42 is formed by a rigid rod of which the lower part 43,is, preferably, sharpened or formed as a cutting edge. This end can betraversed, about its periphery, by longitudinal grooves or interiorly,by a channel ending at the lower level of the wick 8, so as to ease thepassage of the liquid. The piercing pin 42 can be replaced by a cuttingtube functioning in the fashion of a punch, the feeder wick 8 beinglocated within or without the said tube. The piercing pin is preferablyformed of a hard material, such as, e.g., a metal, an alloy, a highmolecular weight substance or a mineral. This piercing pin can also beformed of a porous or fibrous material, wholly or in part, so as to aidthe wick 8 or possibly replace it. Such a material is, for example asintered glass, a sintered metal, or a porcelain. The other end 44 ofthe piercing pin 42 projects beyond the evaporator 9 to permit manualoperation or operation via a tool.

In the variant of FIG. 2, the diaphragm 45 is provided'at-tlie lowerpart of a tube 46 slidingly mounted in the wick tube 6, withsufficiently small play to make the joint sealed with respect to liquid2. The tube 46 contains the wick 8 and supports the evaporator 9 on aflange 47, as is the case in Complementarily, the base 3 of thereservoir 1 comprises on the axes of tubes 6 and 46 a piercing pin 48directed toward the diaphragm 45. It is to be understood that bypressing by any suitable method on the tube 46 to displace it accordingto arrow K, the piercing of diaphragm 45 is carried out by the piercingpin 48. The travel of tube 46 is limited by an abutment 49.

According to another variant (FIG. 3) the tube 6 is closed at its lowerpart by a partition 51, and possesses, a little above this partition,one or more internal pinched swellings 52, playing the part of adiaphragm and which are more fragile than the rest of the wall of thetube 6. A blade 53 operated by a rod 54 allows the sectioning orbreaking the swellings 52 by a sliding movement at the moment of puttingthe apparatus into operation. The blade 53 can also be located laterallyof the swellings, sectioning then taking place by displacement of theblade 53 about the axis of the tube 6.

The sectioning of the swellings can also be carried out by means of adisplaceable tube moving from top to bottom of the tube 6 or effecting arotational movement in the interior thereof.

The construction of the apparatus according to the invention shown inFIGS. 4 to 7 is remarkable for the fact that the apparatus comprisesmeans for allowing the maintenance of atmospheric pressure on the freesurface of liquid 2. In the case of FIGS. 4-6, these means areconstituted by a tube 15, suitably capillary, starting from an orificein the face 4 of the reservoir 1 and joining the gaseous inner volume 16of reservoir 1 to the atmosphere. Preferably the height and position oftube 15 are determined such that liquid 2 cannot escape therethrough ifthe apparatus is overturned. In the example of FIG. 4, the tube 15 isparallel to the wick tube 6 and located a short distance away. If thereservoir is of cylindrical shape and it is arranged that at the startit is filled to a little less than half full, the height of the tube 15is substantially equal to half the height of reservoir 1.

communication tube is formed by a supply pipe 17 starting from anorifice on face 4, and the free end of which is furnished with a loadedfloat 18. The end of the pipe 17 is thus located in the gaseous phase,whatever the position of the apparatus, which enables almost completefilling of the reservoir 1.

The materials usable in the construction of the pressure equalizingmeans are, particularly, those which have been indicated for thereservoir I. The material may be the same as that of the reservoir 1 ordifferent therefrom. It can also, in the case of a supple pipe, be anatural or synthetic elastomer or a metal in the form of a series ofcylinders fitted together as in a telescope and sealingly articulated.

In all case s the pressure equali iing means allows the gaseous 7 volume16 to be maintained at atmospheric pressure, which According to theconstruction of FIG. 7, the atmosphere suppresses any efflux of liquid 2toward the evaporator 9 if the apparatus heats up, particularly in thesun. The complete saturation of evaporator 9 could in effect generatedangerous escapes in the case of phosphorous insecticides.

The wick tube 6 also allows, as will now be seen, the assurance of extrasafety by permitting the sealing closure of reservoir 1, at the will ofthe user, or by the destructible closure device described above, frommanufacture up to the first time of use.

The different closure systems and systems for putting into operationdescribed above for the safety tube 6 are equally applicable to theatmospheric pressure equalizing means described above when this is arigid tube. The application of the systems of closure or putting intoaction can take place separately or simultaneously on the safety tubeand the pressure equalizing tube. An example ofa similar constructionwill be given with reference to FIGS. 4 to 6.

The evaporation apparatus described above can be provided with adiffuser hood or cover, with a view, for example, to protecting theevaporative surface from shocks and to prevent its accidental contactwith linen, clothing, furniture or skin. Such diffusers are particularlyuseful when the liquid to be evaporated is toxic or when it can catchfire on the material of the evaporator. Such a diffuser can be, forexample, a grill, a perforated plate, a textile or metallic tissue or anexpanded metal. The shape of the diffuser is not critical and can bevaried having regard to the type of protection needed and the appearanceof the apparatus. Particularly the diffuser can be vertical, oblique,horizontal or along any curve. The diffuser can also form part ofa unitforming a protective casing for the reservoir of the apparatus. Thislatter can then be constructed of a material of low density, for examplea polymer or elastomer.

There will now be described, with reference to FIGS. 4 to 6, onepreferred embodiment of the invention which makes use ofseveral of thedetails defined above. This apparatus forms a safety evaporatorparticularly adapted for use with toxic liquids such as the phosphoricester insecticides.

The reservoir 1 is of low-pressure high-density polyethylene and is madein two parts In and lb assembled by welding along the line a-a. The wicktube 6 is constructed of the same material, as is also the pressureequalizing tube which is integral with the tube 6. Each of the tubes 6and 15 is obturated by a diaphragm 61 and 62 (FIG. 6) formed at themoment of moulding of the element. The unit of wick tube 6 and pressureequalizer tube 15 is welded to the inside at the top of the reservoir 1,before assembly ofthe two parts la and lb thereof.

The reservoir I bears a mouth 63 to allow filling; the walls of thismouth 63 are sufficiently fine to allow closure by pinching and thermalwelding after filling. The wick 8 is offelt and formed by two adjacentparallel belts. The evaporator 9 is a disc of rigid felt, and it issupported by six plates 64 of polyethlene, integral with reservoir 1.The joint between the evaporator 9 and the wick 6 is formed by a forcefit of this latter in a central hole in the evaporator. The apparatuscomprises a piercing pin 65 of polyamide resin passing between the twobands of felt forming the wick 6. A second piercing pin 66 of polyacetalresin is located in the pressure equalizing tube 15.

The pointed end of the piercing pin 65 has an array of grooves 67 whilethe piercing pin 66 has a lateral channel 68 extending from one end tothe other (FIG. 6).

A slope 69 is provided in the base 3 of reservoir] to collect theimpurities which may be precipitated. The base 3 of reser' voir I has atits middle a little basin 7] for reception of the point of piercing pin65.

The whole apparatus is located vertically by the crosspicces 73 in acylindrical metallic diffuser casing formed by an expanded metal grille74 fixed by insertion into two discs 75 and 76 of folded sheet metal.The upper disc 75 is pierced at its center by a hole 77 allowing theoperation of the common head 78 ofthe piercing pins 65 and 66. Thecrosspieces 73 are fixed by tenons 79 engaged in mortices 81 of the wall4. The

filling with the liquid 2 to be evaporated is done via the mouth 63 upto the level N, chosen so as to permit no overflow of liquid whateverthe position of the apparatus in use.

Putting the apparatus into action is effected by simple pressure on thehead 78 of the piercing pins, which has the effect of piercing the twodiaphragms 61 and 62 and of permitting the liquid 2 to reach the base ofthe wick 8.

On turning the apparatus upside down, cessation of functioning isobtained.

By way of example, the following numerical details are given:

The reservoir of the preceding apparatus has a total capacity of 450 ml.and is filled to 40 percent of its volume with the following solution:

DDVP 7.5% 2-octanol 3.0% lsoper L 89.5%

lsoper L is a mixture of a branched chain aliphatic hydrocarbons made byESSO STANDARD, consisting of a mixture of decanes, undecanes anddodecanes.

The apparatus is equipped with a felt disc 9 of rayon, 40 mm. across.Putting it to use is carried out as noted, and the apparatus is placedin a constantly ventilated room kept at Zlt 1 C.

A regular evaporation of l.l:O.l5 gm., corresponding to 82:]0 mg. ofDDVP, is noted over a period of 120 days.

In a test designed to determine the efficacy of of the apparatus, houseflies were introduced into a normal living room of volume about 30 ms,the doors and windows ofwhich were closed throughout the test, thetemperature ofwhich was kept at 25:1" C.; an apparatus such as definedabove was placed in the room; the percentage of flies fallen-(KD) wasnoted with respect to the elapsed time in minutes. The following averageresults on ten tests were noted:

KD 50 37:5 minutes KD 65:7 minutes The same test was repeated in thesame room, but with one window open, but provided with a mosquito net.The follow ing average results on ten tests were noted:

KD 50 52:6 minutes KD 90 98:6 minutes Tests were, on the other hand,carried out in the same conditions with a commercial evaporativecomposition on the basis of DDVP and a high molecular weight resin, theresults observed with closed and open window respectively were asfollows:

KB 50 3515 minutes :30 minutes KB 90 63:7 minutes 200:35 minutes Thesevarious results illustrate the property of the apparatus of compensatingby stronger evaporation the losses due to the aeration of the room atthe same time as showing their good efficacy.

Tests carried out in various positions of the apparatus showed that, onthe other hand, no overflow of toxic liquid was to be feared. Likewise,tests carried out between l5 C. and +55 C. showed that no overflow dueto increased pressure was to be feared.

The apparatus shown in FIG. 7 is formed entirely of aluminum, thereservoir l-diffuser 82 unit comprises three pieces assembled by fittingtogether; the lower part 1c is in the form of a truncated cone; theupper part of the reservoir 1 is a disc pierced at its center to allowthe passage of the wick 8. The diffuser 82 is of perforated sheet metal.The safety tube 6 is welded to the wall 4 and acts as cross piece. Itsbase 83 is closed and rests on the annular ridge 84 on the base ofreservoir l.

The wick 8 is form of a tube of bleached unsizcd cellulose card set in adisc of identical material. A piercing pin 85 of steel passes throughthe inside of wick 8. Putting it into use takes place by a light tapwith a hammer on the top 86 of the diffuser 82. The elasticity thereofallows the driving of the piercing pin through the base 83 of tube 6 andthe liquid then comes into contact with wick 8.

The maintenance of the interior of reservoir 1 at atmospheric pressureis ensured by a flexible pipe 17 crossing wall 4 and bearing float 18.

The reservoir 1 of such an apparatus has a total capacity of 300 ml. andis filled to 45 percent of its capacity with a 2 percent solution inZ-butoxyethanol of a volatile floral composition. The apparatus isequipped with an evaporative surface of area 30 cm. and the variouspieces are assembled by setting them together. The apparatus is put touse and placed in a living room where the temperature is maintained at20-22" C. The perfume is rapidly liberated and extends throughout theatmosphere of the room.

Daily weighings showed a regular evaporation of 1.110.] grams per day. 7

Whatever the position of the apparatus, no outflow of the liquid insidetook place. i

The apparatus underwent temperature changes of 25 C. without anyoverflow of its contents.

FIGS. 8 and 9 show a construction of the apparatus according to theinvention with a nondestructible closure device, which is neverthelessmuch simpler and surer in its functioning than the known valveapparatus.

In this embodiment the communication of the tube 6 with the atmosphereis interrupted by means ofa plug 21, provided with a manipulation head22 which extends across the evaporator 9 and which slides sealingly inthe tube 6. The plug 21 is located in the projection of wick 8 to whichit is fixed, e.g., by engagement and adherence at 23.

Naturally, the wick 8 is likewise slidably mounted in tube 6. In thoseconditions, when the plug 21 is in the lower position (Position of FIG.8) the tube 6 is obturated and the evaporator 9 is not fed. When theplug 21 is pulled upwards (FIG. 9) the wick 8 contacts the evaporator 9again and the apparatus is put back into operation. Preferably, in thiscase retaining means are provided for the evaporator so as to preventits being entrained by the displacement ofthe wick 8.

The apparatus shown in FIG. 10 is made entirely from plastic material.The reservoir 1 is of polyvinyl chloride; it is obtained by blowextrusion and the unit of the wick tube 6 and the equalization tube 15,of the same material, is obtained by injection moulding. This unit has acommon cylindrical well 93 into which a plug 94 can engage, to whichplug is attached a wick 8 of a felt of wool and cotton. The Unit 6,15 isfixed in the opening of reservoir 1 by welding. The evaporator 9 is ofafelt of wool and cotton of type identical to that used for the wick 8.The diffuser 95 is a see-through cap of polypropylene obtained byinjection moulding, and it is crossed axially by a rod 96 fixed to plug94, provided with a manipulation ring 97 and a stop 98. Putting thisapparatus to use is effected by raising the plug 94 by means of ring 97,which has the effect of contacting wick 8 with evaporator 9, the plug 94moving to 940.

By way of illustration, the following tests are noted: The reservoir 1of the preceding apparatus has a total capacity of 500 ml. and is filledto 40 percent of its capacity with a solution of water containing 3.3percent of concentrated deodorant known under the mark AlR-WlCK-Ol7.Filling is effected via the tube 6, then the wick 8 and plug 84 are putin position, while the evaporator has a surface of 20 cm. The plug 24 israised and the apparatus is placed in a living room where thetemperature is maintained at 20/22 C. The relative humidity .isinitially 35 percent. Daily weighing allowed the determination oftheregular evaporation of 7.2:06 grams per day; the room is thuspermanently protected against bad odors.

Whatever the position of the apparatus, no escape of the liquid frominside took place. The apparatus underwent any temperature differencewithout overflow.

In another construction, the reservoir having a total capacity of 780ml. is filled to 40 percent of its volume with a [0 percent aqueoussolution of formaldehyde. The evaporative surface is 32 cm. The plug 94is raised and the apparatus placed in a living room the temperatureofwhich is maintained at 20- 22 C. and in which the relative humidity isinitially 35 percent; Daily weighings showed a regular evaporationof4.5i0.2 grns. per day; the atmosphere in the room is thus permanentlyprotected from germs and bacteria, and pathogenic agents in general.

In the use of the apparatus according to the present invention, it isplaced supported on its face 3 as shown in FIG. 1. The liquid 2 isabsorbed by the wick 8 which feeds the evaporator 9 the surface of whichensures the evaporation of the liquid and its distribution intotheatmosphere. 1

Starting with filling, as has already been noted, the quantity of liquidintroduced into the reservoir 1 should be such that in all positionsthereof the free surface A of the liquid 2 should be located below theorifice 7 and it can be seen that the tube 6 forbids any escape ofliquid. Furthermore, in this case, simply turning the apparatusupside-down allows the stopping of the feed to the wick 8 and, as aresult, generates the cessation, after a certain delay, of theevaporation. This permits the liquid 2 to be preserved during timesofstoppage.

It is often the case with the organophosphorous insecticides,particularly DDVP, that a deposit of solid impurities forms at the baseof reservoir 1. To avoid this deposit clogging the wick 8 and thuspreventing the rise of liquid 1 toward the evaporator 9, it is provided,according to the invention, that the base is so constructed that it hasa convex surface at the center as shown in FIG. 4. In this case, theimpurities 2a collect together by gravity at the edge of the reservoir.

The invention thus provides notable progress in the field of diffuserapparatus. It permits at the same time easy and economic manufacture ofthese such apparatus, gives the user a large area of use, and avoids anydanger, notably in the case of phosphorous insecticides.

It is clear that the invention is not limited to the constructionsdescribed and that one can make variations thereto. Thus, the wick tube6 can comprise a radial swelling constituting an expansion'vessel, whenit is desired to prevent loss of liquid 2 due to excess pressure withoutrecourse to an atmosphere communication tube 15 or a flexible pipe 17.

We claim: 1

1. Apparatus for diffusion of volatile liquids into the atmosphere byevaporation comprising a reservoir containing the liquid to beevaporated into which dips a feeder wick joined to an evaporator mountedon a wall of this reservoir, and a tube carried by the said wall insidethe reservoir and directed with its interior orifice towards the basethereof, this tube surrounding the wick for at least part of its height,the said apparatus being characterized in that it comprises adestructible closure device interrupting the communication of theinterior orifice of the wick tube with the atmosphere before use andmeans to destroy the said closure device at the moment of putting touse.

2. Apparatus according to claim 1 characterized in that the base of thereservoir as seen from the interior orifice of the wick tube, includes abasin separated from the rest of the base of the reservoir by an annularridge.

3. Apparatus according to claim 1 and characterized in that thereservoir carries a tube communicating the gaseous volume inside to theatmosphere.

4. Apparatus according to claim 3 and characterized in that theatmosphere communication tube is located parallel to the wick tube andat a height such that its interior orifice is situated above the levelof the liquid, whatever the orientation of the reservoir.

5. Apparatus according to claim 3 and characterized in that theatmospheric communication tube is formed by a flexible pipe connected tothe wall of the reservoir bearing the evaporator, the free end of whichpipe is attached to a float.

6. Apparatus according to claim 1, characterized in that the interiororifice of the wick tube is sealed initially by a diaphragm means beingadditionally provided to ensure perforation of this diaphragm when theapparatus is put to use.

7. Apparatus according to claim 6 and characterized in that thediaphragm perforation means includes a piercing pin located in the wicktube and of which the other end extends to the outside to allow ofmanualoperation.

8. Apparatus according to claim 1 comprising a second tube communicatingthe liquid reservoir with the atmosphere in that this tube is initiallysealed by a diaphragm, means being provided to allow the perforation ofthis diaphragm when the apparatus is put to use, and furthercharacterized in that the interior orifice of the wick tube is sealedinitially by a diaphragm, means being additionally provided to ensureperforation of this diaphragm when the apparatus is put to use.

9. Apparatus according to claim Scharacterized in that it comprises twopiercing pins to perforate the diaphragms of the two tubes and in thatthese two piercing pins are fixed to the same actuation button to allowtheir operating simultaneously.

10. Apparatus for diffusion of volatile liquids into the atmosphere byevaporation comprising a reservoir containing the liquid to beevaporated into which dips a feeder wick joined to an evaporator mountedon a wall of this reservoir, and a tube carried by the said wall insidethe reservoir and directed with its interior orifice towards the basethereof, this tube surrounding the wick for at least part of its height,the said apparatus being characterized in that it comprises anondestructible closure device interrupting the communication of theinterior orifice of the wick tube with the atmosphere before use and inthat the closure device comprises a sealing plug located in theprojection of the feeder wick and which crosses the evaporator, the unitformed by the plug and the wick being slidable between a closureposition at which the plug obturates the wick tube and an open positionin which the plug is pulled beyond the evaporator, this latter beingthen in contact with the feeder wick.

11. Apparatus according to claim 10 characterized in that the wall ofthe reservoir carrying the evaporator is covered by a movable lid havinga diffuser wall, which lid is set on to the body of the reservoir andwhich carries cutting lines which end in a tear-off tab.

